How to call one function which has a function as a parameter in main()?

Question

Example
We define a function: string month_convert(string month2, string month_fun(int& month)){}.
And now I don't know how to call this function in main. Does anybody has any idea?
https://code.sololearn.com/cS3W2egl3CEN/?ref=app
https://code.sololearn.com/cuW1bgV4jC3J/?ref=app

Answer 1

Martin Taylor Why would the declaration for month_convert() be invalid? In C++, I think the following are equivalent, at least when specifying a function as parameter:

string month_fun( int& )
string ( *month_fun )( int& )
string ( &month_fun )( int& )

Then again, I usually use template parameters for callables. I found it suggested here:

https://ncona.com/2019/05/passing-functions-as-arguments-in-cpp/

Whether the nested arguments are named should have no bearing, since the parameter would be adjusted to a function pointer either way. If anything, the following code compiles on SoloLearn:

https://code.sololearn.com/c17A226a10A2/?ref=app

If I am wrong please correct me.

Answer 2

Well,you can use function pointers
if you are trying to pass a function as an argument to a function in C/C++...??

That's all I understood by your problem...

Answer 3

Ok, I will give you the whole code and then you see what can be done.

Answer 4

Sorry I haven't come so far. I still have not using template and foo, so I don't know these items yet. Please take one step bsck.

Answer 5

What I don't know here is how to use a reference sign & in main function when I am calling a function.

Answer 6

I hope I will soon make it corect. But first I more study.